Says Tycho from Penny-Arcade:

I purchased twenty fluid ounces of Halo 3 “Limited Edition Mountain Dew Game Fuel” in the hopes that it would taste so horrible that we’d get a strip out of it. ┬áBefore I read the ingredients in preparation for this post, I often found myself desirous of this strange liquid – a liquid the precise color of tubercular sputum. I would trip over to Seven Eleven to obtain it, tipping a small portion onto the concrete for the Spartans we lost at Reach. Once I discovered that the soda contained a compound called “Brominated Vegetable Oil,” my ardor was diminished for some reason. The flavor of the beverage is not unpleasant, especially if you like bromide.

I see the stuff all over the place on sale, and I still can’t bring myself to try it again.